Analysis of the causes of wear on the tool holder of CNC shearing machine?

In the field of metal processing, CNC shearing machines have become indispensable key equipment in many industries due to their high precision and efficiency. As the core executing component of the CNC shearing machine, the performance of the knife holder directly affects the shearing quality and the service life of the equipment. However, in actual use, the problem of tool holder wear often occurs, which not only affects the cutting accuracy but may also shorten the service life of the equipment. Exploring the causes of wear on the tool holder of CNC shearing machines is of great significance for improving equipment operating efficiency and reducing maintenance costs.

1. Wear caused by mechanical force

During the cutting process of a CNC shearing machine, the tool holder is subjected to enormous mechanical pressure. When cutting plates with high hardness or thickness, the mechanical pressure on the cutting edge of the tool holder will significantly increase. This sustained high pressure can easily cause fatigue in the tool holder material, leading to fracture or minor collapse. For example, when cutting stainless steel plates, due to the high hardness of stainless steel, small cracks will gradually appear at the cutting edge of the tool holder during repeated cutting processes. With the increase of cutting times, these cracks will continue to expand, ultimately leading to increased wear of the tool holder. In addition, if the material selection of the tool holder is improper, its strength and toughness cannot meet the shear requirements, and wear will occur faster under the action of mechanical force.

2. Wear caused by the influence of heat

During the cutting process, the intense friction between the knife holder and the sheet will generate a large amount of heat. These heats will cause a sharp increase in temperature on the cutting edge of the tool holder, leading to a series of problems. On the one hand, temperature changes can cause thermal stress inside the tool holder material. When the thermal stress exceeds the material's bearing capacity, cracks will occur. On the other hand, high temperature can also cause plastic deformation of the tool holder material, resulting in inward or downward collapse of the cutting edge, changing the shape of the cutting edge and affecting shear accuracy. For example, during continuous high-speed shearing, the temperature at the cutting edge of the tool holder may reach several hundred degrees Celsius. Prolonged heat accumulation can reduce the hardness and wear resistance of the tool holder material, thereby accelerating wear.

3. Wear caused by chemical reactions

In the usage environment of CNC shearing machines, chemical reactions may occur between the tool holder material and the workpiece material, leading to wear. For example, when using a hard alloy tool holder to shear certain metal sheets containing active elements, under high temperature and pressure, elements such as cobalt in the hard alloy may diffuse with elements in the workpiece material, changing the chemical composition and metallographic structure of the tool holder material, reducing its hardness and increasing its brittleness, thereby accelerating wear. In addition, oxygen in the air and additives in the cutting fluid may also undergo chemical reactions with the tool holder material, generating loose and fragile oxides that are easily carried away by chips, leading to tool holder wear.

4. Wear caused by adhesion phenomenon

For some materials with high viscosity, such as low carbon steel, aluminum, etc., it is easy to form chip layers or chip lumps on the front cutting surface of the tool holder during the shearing process. The formation of chip deposits can change the actual geometric shape of the cutting edge, increase cutting force, and lead to increased wear of the tool holder. Meanwhile, when the debris tumor falls off, it may take away the material on the surface of the tool holder, causing damage to the tool holder surface. In addition, adhesive loads can also cause tensile stress on the cutting edge of the tool holder, leading to coating separation and exposure of the underlying layer or substrate, further accelerating the wear of the tool holder.

5. Wear caused by vibration factors

During the operation of the CNC shearing machine, if the rigidity of the machine tool is insufficient, the tool holder is not firmly installed, or the workpiece is not stably clamped, vibration will occur. Vibration can cause uneven force on the tool holder during the shearing process, leading to unstable contact between the tool holder and the plate and exacerbating wear. For example, when the tool holder is too long or the hardness of the tool holder is insufficient, high-frequency vibration is easily generated during the cutting process, causing frequent collisions between the tool tip and the workpiece surface, resulting in direct fragmentation of the tool tip and accelerating the wear rate of the tool holder.
The wear of the CNC shearing machine tool holder is the result of multiple factors working together. In order to reduce the wear of the knife holder and extend the service life of the equipment, it is necessary to start from multiple aspects. When selecting the material for the tool holder, the appropriate material should be chosen based on the characteristics of the processing material; Reasonably set cutting parameters to avoid excessive cutting speed, feed rate, and cutting depth; Ensure that the tool holder is securely installed, improve the rigidity of the machine tool, and reduce vibration; At the same time, choose the appropriate cutting fluid to provide sufficient cooling and lubrication. Only in this way can the wear of the CNC shearing machine tool holder be effectively reduced, and the operating efficiency and processing quality of the equipment be improved.